Ctalk adds classes, methods, operator overloading,
inheritance, and complex object expressions to otherwise standard C programs. Programs can use only a few Ctalk objects and methods in an otherwise standard C program, but the language can be used to write entire programs also. Ctalk works on most if not all of the systems that support GCC, the GNU C compiler. The package includes the language, class and run-time libraries, example programs, tutorial, and language reference.

Gearmand is the job server component of Gearman.
Gearman provides a generic framework to farm out
work to other machines, dispatching function calls
to machines that are better suited to do work, to
do work in parallel, to balance the load of
processing, or to call functions between
languages.

ccglue is a complementary tool to cscope and ctags. The tool builds a cross-reference symbol database from cscope (and ctags) databases that can be used to display dependency-graphs (aka call-trees, code flow). Visualization can be done with the Vim CCTree plugin or the built-in stand-alone command-line tracer.

liwc is a tool suite which includes programs for converting C++ comments to C comments, removing C comments, printing string literals, and converting characters to trigraphs and trigraphs to characters.

fpgatools is a toolchain for programming flexible programmable gate arrays (FPGAs). The only supported chip at this time is the xc6slx9, a cheap (circa $10 U.S.) but powerful 45nm-generation chip with about 2400 LUTs, block ram, and multiply-accumulate devices. The principles of fpgatools are to reach the maximum physical performance of the chip, to provide fast development cycles, to be an independent toolchain which only depends on other Free Software, and to be a lightweight C implementation without a GUI.

cmocka is a unit testing framework for C with mock objects. There are a variety of C unit testing frameworks available supporting different platforms and compilers. Some development requires a lot of different compilers and older versions, which makes it difficult to use unit testing frameworks. The idea of CMocka is that a test application only requires the standard C library and CMocka itself to minimize the conflicts with standard C library headers, especially on a lot of different platforms.

libXbgi is a compatibility library that aids in porting old programs written for Turbo/Borland C to X11, on Linux and other Unix-like systems. It also provides extensions for RGB colors and mouse support.

pyC11 is a grammar to parse programs in the C programming language following ISO/IEC 9899:2011. It is written using pyPEG, a parsing framework for Python. The grammar supports Python 2.7 and 3.x. The test bench requires py.test.

Generic Makefile for C Projects is a generic makefile that builds a binary from C source code files. Any number of build modes are supported - Release and Debug are predefined. The CFlags and LFlags variables can be defined in a mode dependent way, i.e. CFlags_Debug. File dependencies are generated by the compiler (-MMD flag for preconfigured GNU compiler) and included by the makefile automatically. All output is written under a single target directory. It supports source files with the same name that are located in different directories. You can use wildcards to add any number of source files.

snappy-c is a C port of the google snappy compressor (http://code.google.com/p/snappy/). The compressor is very fast with a reasonable compression ratio. It is mainly useful for projects that cannot integrate C++ code, but want snappy. It also contains a command line tool, a benchmark, random test code, and a fuzz tester. The compression code supports scather-gather and linear buffers. The scather gather code is ifdefed (-DSG) and can be removed with unifdef.